Electro-hydraulic brake and control method therefor

ABSTRACT

According to at least one embodiment, the present disclosure provides an electro-hydraulic brake comprising: a main brake unit configured to provide braking hydraulic pressure to a plurality of wheel cylinders by driving a motor; an auxiliary brake unit connected to the main brake unit to be filled with high-pressure braking hydraulic pressure, and configured to provide braking hydraulic pressure to the plurality of wheel cylinders when an operation error of the main brake unit occurs; a main battery configured to supply power to the main brake unit and the auxiliary brake unit; and an auxiliary battery configured to supply power to the auxiliary brake unit when the main battery fails, wherein the auxiliary brake unit comprises an auxiliary brake control unit that controls charging and discharging of the auxiliary battery, and a power module that monitors a state of the main battery and transmits the state to the auxiliary brake control unit, and a battery management module that monitors a state of charge (SOC) of the auxiliary battery and transmits the state of charge to the auxiliary brake control unit.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based on, and claims priority from, Korean PatentApplication Number 10-2021-0104058, filed Aug. 6, 2021, the disclosureof which is incorporated by reference herein in its entirety.

TECHNICAL FIELD

The present disclosure relates to an electro-hydraulic brake system anda control method therefor.

BACKGROUND

The description in this section merely provides background informationrelated to the present disclosure and does not necessarily constitutethe related art.

Electro-hydraulic brakes use an electric motor to generate hydraulicpressure. Electro-hydraulic brakes transmit hydraulic pressure to wheelcylinders to generate braking force in each wheel cylinder. Theelectro-hydraulic brake makes it easy to individually control thebraking force generated by each wheel cylinder. Accordingly, theelectro-hydraulic brake may easily implement functions such asElectronic Stability Control System (ESC) or Anti-Lock Brake System(ABS).

Electro-hydraulic brakes have a high risk of failure because many partsare made up of electronic equipment. When the electro-hydraulic brakefails while a vehicle is driving, there is a risk of a major accident.Accordingly, a redundancy system may be necessary that allows anauxiliary braking system to operate when the main braking system of theelectro-hydraulic brake does not operate normally.

Even when a redundancy system is implemented by adding the auxiliarybraking system to the main braking system, the main braking system andthe auxiliary braking system share a single power source. When a failureoccurs in the main braking system, braking force may be generated in avehicle using the auxiliary braking system. However, when a powerfailure occurs in the vehicle, a situation may arise in which not onlythe main braking system but also the auxiliary braking system do notoperate normally. In a redundancy situation, when the auxiliary brakingsystem does not operate normally or its performance is degraded, it maynot be able to supply the required braking force to a vehicle and amajor accident may occur.

SUMMARY

According to at least one embodiment, the present disclosure provides anelectro-hydraulic brake system comprising: a main brake unit configuredto provide braking hydraulic pressure to a plurality of wheel cylindersby driving a motor; an auxiliary brake unit connected to the main brakeunit to be filled with high-pressure braking hydraulic pressure, andconfigured to provide braking hydraulic pressure to the plurality ofwheel cylinders when an operation error of the main brake unit occurs; amain battery configured to supply power to the main brake unit and theauxiliary brake unit; and an auxiliary battery configured to supplypower to the auxiliary brake unit when the main battery fails, whereinthe auxiliary brake unit comprises an auxiliary brake control unit thatcontrols charging and discharging of the auxiliary battery, and a powermodule that monitors a state of the main battery and transmits the stateto the auxiliary brake control unit, and a battery management modulethat monitors a state of charge (SOC) of the auxiliary battery andtransmits the state of charge to the auxiliary brake control unit.

According to at least one embodiment, the present disclosure provides amethod for controlling an electro-hydraulic brake of a vehicle, themethod comprising: an inspection process of inspecting states of a mainbattery and an auxiliary battery using a power module and a batterymanagement module; a determination process of transmitting the states ofthe main battery and the auxiliary battery to an auxiliary brake controlunit to determine a failure; a failure control process of controlling toperform a failure mode when a failure of the main battery or theauxiliary battery occurs; and a normal control process of controlling toperform a normal mode when the main battery and the auxiliary batteryare normal.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of an electro-hydraulic brake system accordingto an embodiment of the present disclosure.

FIG. 2 is a block diagram illustrating an auxiliary brake unit of anelectro-hydraulic brake according to an embodiment of the presentdisclosure.

FIG. 3 is a flowchart illustrating a method for controlling anelectro-hydraulic brake auxiliary brake control unit according to anembodiment of the present disclosure.

FIG. 4 is a flowchart illustrating a method for controlling anelectro-hydraulic brake battery management module according to anembodiment of the present disclosure.

FIG. 5 is a flowchart illustrating a method for controlling anelectro-hydraulic brake power module according to an embodiment of thepresent disclosure.

DETAILED DESCRIPTION

The electro-hydraulic brake or electro-hydraulic brake system accordingto an embodiment includes a separate auxiliary power supply to operatean auxiliary braking system normally by using the auxiliary power supplyeven when a failure occurs in a main power supply of a vehicle.

The aspects of the present disclosure are not limited to the foregoing,and other aspects not mentioned herein will be able to be clearlyunderstood by those skilled in the art from the following description.

Hereinafter, some embodiments of the present disclosure will bedescribed in detail with reference to the accompanying drawings. In thefollowing description, like reference numerals preferably designate likeelements, although the elements are shown in different drawings.Further, in the following description of some embodiments, a detaileddescription of related known components and functions when considered toobscure the subject of the present disclosure will be omitted for thepurpose of clarity and for brevity.

Additionally, alphanumeric codes such as first, second, i), ii), (a),(b), etc., in numbering components are used solely for the purpose ofdifferentiating one component from the other but not to imply or suggestthe substances, the order, or sequence of the components. Throughoutthis specification, when parts “include” or “comprise” a component, theyare meant to further include other components, not excluding thereofunless there is a particular description contrary thereto. The termssuch as ‘unit,’ ‘module,’ and the like refer to one or more units forprocessing at least one function or operation, which may be implementedby hardware, software, or a combination thereof.

FIG. 1 is a block diagram of an electro-hydraulic brake according to anembodiment of the present disclosure.

Referring to FIG. 1 , an electro-hydraulic brake 100 may include a mainbrake unit 110, an auxiliary brake unit 120, a main battery 130, and anauxiliary battery 140.

The main brake unit 110 is connected to the main battery 130 andreceives power from the main battery 130. The auxiliary brake unit 120is connected to the main battery 130 and receives power from the mainbattery 130. In addition, the auxiliary brake unit 120 is connected tothe auxiliary battery 140 and receives power from the auxiliary battery140 when the main battery 130 fails.

The main brake unit 110 provides braking hydraulic pressure to aplurality of wheel cylinders by driving a motor. The auxiliary brakeunit 120 is connected to the main brake unit 110 to be filled withhigh-pressure braking hydraulic pressure. The auxiliary brake unit 120provides braking hydraulic pressure to the plurality of wheel cylinderswhen an operation error or failure of the main brake unit 110 occurs.When an operation error occurs in the main brake unit 110, thehigh-pressure braking hydraulic pressure stored in the auxiliary brakeunit 120 is quickly supplied to the wheel cylinder to enable emergencybraking. Due to an operation error of the main brake unit 110, anoperation error of various valves controlling a hydraulic circuit orinability to drive a motor may occur.

The main brake unit 110 may include all or part of a pedal cylinder, amaster cylinder, a hydraulic unit, a hydraulic connection unit, and aplurality of valves.

The auxiliary brake unit 120 may include all or part of an auxiliaryhydraulic unit, an auxiliary accumulator, an auxiliary detour unit, anauxiliary sensing unit, and a plurality of valves.

The configuration and control method of the hydraulic circuit of themain brake unit 110 and the auxiliary brake unit 120 are not limited toa specific embodiment, and since it is a technique known to thoseskilled in the art related to the present disclosure, a detaileddescription thereof will be omitted.

FIG. 2 is a block diagram illustrating an auxiliary brake unit of anelectro-hydraulic brake according to an embodiment of the presentdisclosure.

Referring to FIG. 2 , the electro-hydraulic brake 100 may include anauxiliary brake control unit 121, a power module 122, a batterymanagement module 123 (BMS), and a communication unit 124.

The power module 122 may monitor and control the current state of themain battery 130. The power module 122 may monitor the current andvoltage states of the main battery 130. The power module 122 maytransmit the state of the main battery 130 to the auxiliary brakecontrol unit 121. The power module 122 may be used by distributingpower. The main battery 130 transmits power to the power module 122using Vbat1 and Vbat2. The power module 122 may include a switch. Theswitch enables switching of power between the main battery 130 and theauxiliary battery 140.

The battery management module 123 may monitor and control the auxiliarybattery 140. The battery management module 123 may monitor the current,temperature, balance, and state of charge (SOC) of the auxiliary battery140. In this connection, the balance refers to a power balance of theauxiliary battery 140. The battery management module 123 may transmitthe state of the auxiliary battery 140 to the auxiliary brake controlunit 121. In order to prevent overcurrent when power is output, thebattery management module 123 may include a circuit. The batterymanagement module 123 may include a fuse. The fuse preventsshort-circuit.

The auxiliary brake control unit 121 commands the power module 122 tocontrol the main battery 130 by using the information received from thepower module 122. The auxiliary brake control unit 121 commands thebattery management module 123 to control the auxiliary battery 140 byusing the information received from the battery management module 123.The auxiliary brake control unit 121 may give a switching commandbetween the main battery 130 and the auxiliary battery 140 to the powermodule 122. In this connection, the auxiliary brake control unit 121 maybe a micro control unit (MCU).

The auxiliary brake control unit 121 manages a charge amount of theauxiliary battery 140 by using the charge state information of theauxiliary battery 140. In order not to run out of power of the auxiliarybattery 140 when the main battery 130 fails, the auxiliary brake controlunit 121 manages the charge amount of the auxiliary battery 140. Theauxiliary brake control unit 121 controls charging and discharging ofthe auxiliary battery 140 using the battery management module 123. Themain battery 130 supplies power to the battery management module 123using Vbat2 and charges the auxiliary battery 140. Charging of theauxiliary battery 140 is stopped during braking of a vehicle. However,when a failure occurs in the main battery 130, power is output to thebattery management module 123 regardless of whether the vehicle isbraked.

When a failure occurs in the main battery 130, the auxiliary brakecontrol unit 121 may notify a driver with a danger warning light of abraking device. When a failure occurs in the main battery 130, theauxiliary brake control unit 121 may display a braking possible rangeusing the auxiliary battery 140.

The communication unit 124 may support communication between the mainbrake unit 110 and the auxiliary brake unit 120. The electro-hydraulicbrake 100 may use the communication unit 124 to switch braking to theauxiliary brake unit 120 when the main brake unit 110 fails.

The electro-hydraulic brake 100 may include a first pedal sensor and asecond pedal sensor. The main brake unit 110 receives an intention of adriver to brake using the first pedal sensor. The auxiliary brake unit120 receives an intension of a driver to brake by using the second pedalsensor. By using the second pedal sensor, the auxiliary brake unit 120may receive an intention of a driver to brake even when the main brakeunit 110 fails.

FIG. 3 is a flowchart illustrating a method for controlling anelectro-hydraulic brake auxiliary brake control unit according to anembodiment of the present disclosure.

Referring to FIG. 3 , when a driver starts a vehicle, the auxiliarybrake control unit 121 inspects the state of the vehicle (S301). Here,the inspection of the state of the vehicle may include inspecting thestate of not only a braking device but also controllers essential forvehicle control.

The auxiliary brake control unit 121 inspects the states of the powermodule 122 and the battery management module 123 (S302). In theinspection of the power module 122 and the battery management module123, it is determined whether the main battery 130 or the auxiliarybattery 140 has failed (S303). When the main battery 130 or theauxiliary battery 140 fails, the auxiliary brake control unit 121performs a control operation corresponding to a failure mode. Theauxiliary brake control unit 121 determines whether the auxiliarybattery 140 has failed (S304). When the auxiliary battery 140 does notfail, but the main battery 130 fails, the auxiliary brake control unit121 warns a driver of the failure of the main battery 130 and prohibitsdriving of a vehicle (S305).

When only the auxiliary battery 140 fails, the auxiliary brake controlunit 121 warns a driver of the failure of the auxiliary battery 140 anddisplays that a vehicle may be driven (S310). When only the auxiliarybattery 140 fails, the vehicle may be driven, but the power module 122continuously monitors the main battery 130. The auxiliary brake controlunit 121 may determine whether the main battery 130 has failed while thevehicle is driving (S311). When only the main battery 130 fails, theauxiliary brake control unit 121 may display the state of the auxiliarybattery 140 and warn a driver of a back-up braking state (S312).

When the main battery 130 fails, the auxiliary brake control unit 121may warn a driver of a failure of the main battery 130 (S313). Theauxiliary brake control unit 121 may control a vehicle using theauxiliary battery 140. The auxiliary brake control unit 121 may controlto change the power to the auxiliary battery 140 and display a SOC ofthe auxiliary battery to the driver (S313). The auxiliary brake controlunit 121 may display a state in which braking is possible to the driverand induce the driver to stop.

When there is no failure in either the main battery 130 and theauxiliary battery 140, the auxiliary brake control unit 121 displays toa driver that a vehicle is in a drivable state (S306). The auxiliarybrake control unit 121 monitors the main battery 130 using the powermodule 122 (S307). The auxiliary brake control unit 121 controls a SOCof the auxiliary battery 140 by using the battery management module 123(S307). In a vehicle braking situation, the auxiliary brake control unit121 performs braking control using the main battery 130 (S308).

When a vehicle is not turned off, the process returns to S303 tocontinuously monitor the states of the main battery 130 and theauxiliary battery 140 and perform this algorithm until the vehicle isturned off (S309). When the vehicle is turned off, this algorithm ends.

FIG. 4 is a flowchart illustrating a method for controlling anelectro-hydraulic brake battery management module according to anembodiment of the present disclosure.

Referring to FIG. 4 , the auxiliary brake control unit 121 may inspectthe battery management module 123 (S401). The auxiliary brake controlunit 121 may inspect the current, temperature, balance, and SOC of theauxiliary battery 140 as well as imperfections of the battery managementmodule 123 itself.

The auxiliary brake control unit 121 inspects the temperature of theauxiliary battery 140 using the battery management module 123 (S402).When the temperature of the auxiliary battery 140 is outside of a presettemperature range, charging of the auxiliary battery 140 is stopped.When the temperature of the auxiliary battery 140 is within a presettemperature range, the auxiliary battery 140 is charged.

The auxiliary brake control unit 121 inspects the balance of theauxiliary battery 140 using the battery management module 123 (S403).Here, the balance of the auxiliary battery 140 refers to a voltagebalance of the auxiliary battery 140. When the balance of the auxiliarybattery 140 is outside of a preset range, charging of the auxiliarybattery 140 is stopped. When the balance of the auxiliary battery 140 iswithin a preset range, the auxiliary battery 140 is charged.

When there is no abnormality in the temperature and balance of theauxiliary battery 140, the auxiliary brake control unit 121 commands theauxiliary battery 140 to be charged or output (S404). When the auxiliarybattery 140 is used to output the output to the auxiliary brake unit120, the battery management module 123 controls so that overcurrent doesnot occur.

When the auxiliary battery 140 is charged, it is checked whether thecharging state control of the auxiliary battery 140 is normallyperformed (S405). When the charging state control of the auxiliarybattery 140 is abnormal, the auxiliary battery 140 and the batterymanagement module 123 are inspected (S406). A driver is warned toinspect the auxiliary battery 140 and the battery management module 123(S406). When the charging state control of the auxiliary battery 140 isnormal, it is checked whether a vehicle is turned off (S407). When thevehicle is turned off, the auxiliary brake control unit 121 charges theauxiliary battery 140 up to a preset range (S408). When the auxiliarybattery 140 is charged, this algorithm ends.

FIG. 5 is a flowchart illustrating a method for controlling anelectro-hydraulic brake power module according to an embodiment of thepresent disclosure.

Referring to FIG. 5 , the auxiliary brake control unit 121 may inspectthe state of the main battery 130 by using the power module 122 (S501).The power module 122 transmits the state of the main battery 130 to theauxiliary brake control unit 121 (S502). The auxiliary brake controlunit 121 determines whether a vehicle controls braking using the mainbattery 130 (S503).

When braking is controlled using the main battery 130, the power module122 switches power to the main battery 130 (S504). The power module 122monitors the state of the main battery 130 and transmits the same to theauxiliary brake control unit 121 (S505).

When braking is controlled using the auxiliary battery 140, the powermodule 122 switches power to the auxiliary battery 140 (S506). The powermodule 122 monitors the state of the auxiliary battery 140 and transmitsthe same to the auxiliary brake control unit 121 (S507).

This algorithm is repeated while a vehicle is driving (S508). When thevehicle is turned off, this algorithm ends.

According to an embodiment, the electro-hydraulic brake includes aseparate auxiliary power supply, so that a vehicle can be normallybraked using the auxiliary power supply even in the case of a failure ofa main braking system as well as a failure of a main power supply of avehicle.

Although exemplary embodiments of the present disclosure have beendescribed for illustrative purposes, those skilled in the art willappreciate that various modifications, additions, and substitutions arepossible, without departing from the idea and scope of the claimedinvention. Therefore, exemplary embodiments of the present disclosurehave been described for the sake of brevity and clarity. The scope ofthe technical idea of the present embodiments is not limited by theillustrations. Accordingly, one of ordinary skill would understand thatthe scope of the claimed invention is not to be limited by the aboveexplicitly described embodiments but by the claims and equivalentsthereof.

What is claimed is:
 1. An electro-hydraulic brake system of a vehicle,comprising: a main brake unit configured to provide a braking hydraulicpressure to a plurality of wheel cylinders; an auxiliary brake unitconnected to the main brake unit and configured to provide the brakinghydraulic pressure to the plurality of wheel cylinders when a failureoccurs to the main brake unit; a main battery configured to supply powerto the main brake unit and the auxiliary brake unit; and an auxiliarybattery configured to supply power to the auxiliary brake unit when afailure occurs to the main battery, the auxiliary battery comprising: anauxiliary brake control unit configured to control charging anddischarging of the auxiliary battery; a power module configured tomonitor a state of the main battery and transmit the monitored state ofthe main battery to the auxiliary brake control unit; and a batterymanagement module configured to monitor a state of charge (SOC) of theauxiliary battery and transmit the monitored SOC of the auxiliarybattery to the auxiliary brake control unit.
 2. The electro-hydraulicbrake system of claim 1, wherein the auxiliary brake unit furthercomprises a communication unit connected between the auxiliary brakeunit and the main brake unit.
 3. The electro-hydraulic brake system ofclaim 1, further comprising a pedal sensor configured to allow theauxiliary brake unit to receive a driver's braking intention when thefailure occurs to the main brake unit.
 4. The electro-hydraulic brakesystem of claim 1, further comprising a switch configured to switchsupplying of the power between the main battery and the auxiliarybattery.
 5. The electro-hydraulic brake system of claim 1, wherein thepower module is configured to: monitor a current or voltage of the mainbattery; and transmit, to the auxiliary brake control unit, themonitored current or voltage of the main battery.
 6. Theelectro-hydraulic brake system of claim 1, wherein the batterymanagement module is configured to: monitor one or more of a current,temperature and balance of the auxiliary battery; and transmit, to theauxiliary brake control unit, the monitored one or more of the current,temperature and balance of the auxiliary battery.
 7. Theelectro-hydraulic brake system of claim 1, wherein the batterymanagement module comprises at least one of an overcurrent preventioncircuit and a short-circuit prevention fuse.
 8. The electro-hydraulicbrake system of claim 1, wherein the auxiliary brake control unit isconfigured to: receive the state of the main battery and the SOC of theauxiliary battery from the power module and the battery managementmodule, respectively; and select the main battery or the auxiliarybattery to supply the power to the auxiliary brake unit.
 9. Theelectro-hydraulic brake system of claim 1, wherein the auxiliary brakecontrol unit is configured to stop charging the auxiliary battery whenthe vehicle is braking.
 10. The electro-hydraulic brake system of claim9, wherein, when the failure occurs to the main battery, the auxiliarybrake control unit is configured to supply the power to the batterymanagement module regardless of whether the vehicle is braking.
 11. Amethod for operating an electro-hydraulic brake system of a vehicle, themethod comprising: inspecting states of a main battery and an auxiliarybattery; determining, based on the inspected states of the main andauxiliary batteries, whether a failure has occurred to the main orauxiliary battery; in response to determining that the failure hasoccurred to the main or auxiliary battery, controlling theelectro-hydraulic brake system to operate in a failure mode; and inresponse to determining that no failure has occurred to the main orauxiliary battery, controlling the electro-hydraulic brake system tooperate in a normal mode.
 12. The method of claim 11, whereindetermining whether the failure has occurred to the main or auxiliarybattery comprises: determining whether a voltage at the main battery iswithin a preset voltage range; and in response to determining that thevoltage at the main battery is not within the preset voltage range,determining that the failure has occurred to the main battery.
 13. Themethod of claim 11, wherein inspecting the state of the auxiliarybattery comprises inspecting at least one of a current, temperature,balance and charge amount of the auxiliary battery.
 14. The method ofclaim 11, wherein controlling the electro-hydraulic brake system tooperate in the failure mode comprises, in response to determining thatthe failure has occurred to the main battery, prohibiting driving of thevehicle and displaying a warning light.
 15. The method of claim 11,wherein controlling the electro-hydraulic brake system to operate in thefailure mode comprises, in response to determining that the failure hasoccurred to the auxiliary battery, outputting an auxiliary batteryfailure warning and allowing driving of the vehicle.
 16. The method ofclaim 11, wherein controlling the electro-hydraulic brake system tooperate in the normal mode comprises allowing driving of the vehicle,monitoring the main battery while the vehicle is driving, andcontrolling a charging state of the auxiliary battery.
 17. The method ofclaim 16, wherein controlling the electro-hydraulic brake system tooperate in the normal comprises, when the vehicle is braked, stoppingcharging the auxiliary battery and determining whether the failure hasoccurred to the main battery.
 18. The method of claim 11, furthercomprising, in response to determining that the failure has occurred tothe main battery while the vehicle is driving, performing: outputting awarning that the failure has occurred to the main battery; andcontrolling, using the auxiliary battery, an auxiliary brake unit. 19.The method of claim 18, further comprising, in response to determiningthat the failure has occurred to the main battery while the vehicle isdriving, performing: displaying a state of charge of the auxiliarybattery; and displaying a warning light.
 20. The method of claim 11,further comprising, in response to determining that the failure hasoccurred to the auxiliary batter while the vehicle is driving,displaying a state of the auxiliary battery and a backup brakingwarning.